It is hypothesized that the renal toxicity of contrast medium is related to local vasoconstriction. We hypothesize that the protein-stimulated rise in effective RPF and GFR might counteract this intrarenal vasoconstriction and reduce the toxicity of contrast medium in high-risk patients with diabetes. We propose that an infusion of amino acids prior to the administration of contrast dye, will increase renal plasma flow and glomerular filtration rate by approximately 20% and hasten excretion of the contrast agent thereby protecting high-risk patients from contrast nephropathy.